The present invention relates to animal repellents and more particularly to snake repellents and methods for repelling snakes from open and enclosed areas.
The availability of chemical agents for vertebrate pest control varies depending upon the taxon considered. As of 1998 sixty one different active ingredients were registered as mammal control agents with the US Environmental Protection Agency under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) (40 CFR 160) with 41% functioning as lethal control agents and 59% as nonlethal repellents. For bird control about ten ingredients are available agents with 40% being used for lethal control and 60% being used in nonlethal repellents. Prior known mammal and bird repellents are not necessarily effective as snake repellents. Only two products are US EPA registered for snake control. The first product is methyl bromide, and it is used as a lethal fumigant. The second product is advertised as xe2x80x9cDr. T""s Snake-A-Way Snake Repellentxe2x80x9d, and contains naphthalene and sulfur as active agents.
Prior known research efforts to discover and develop effective snake control fall into one of two functional categories: prophylactic or remedial.
Prophylactic products are designed to prevent snakes from accessing areas to be protected, whereas remedial products are designed to extirpate snakes once they have entered an area where they are not desired.
Examples of prophylactic approaches to snake control include physical and chemical barriers. Physical barriers are generally considered to be nonlethal and can include electrical fencing, ordinary fencing, obstructions, polybutene products, or other sticky substances. These methods physically prevent a snake from crossing a protected boundary. Chemical barriers contain chemicals that are used to produce noxious odors or contact irritation. Because of the acute chemical sensibility of snakes such barriers are not crossed because of passive diffusion of the noxious chemical directly around the application zone. Delivery via the passive diffusion methods restricts the zone that the repellent is active.
Remedial methods include lethal and nonlethal methods. Examples of lethal control methods include chemical toxicants. These products are either ingested by the snake, applied to the snake dermally, or applied to the space a snake occupies as a lethal fumigant. Traps and glue boards may be used as lethal or nonlethal remedial methods.
Nonlethal remedial methods include using chemicals repellents, that act as irritants, to motivate a snake to abandon a refugium once it has entered that space. Various organic solvents, such as paint thinners, creosote, kerosene, and flammable oils, have been used for this purpose under experimental situations but these chemicals raise clear safety and environmental concerns. There are no prior known chemicals that are experimentally and practically effective at driving snakes out of refugium that are environmentally safe and safe for humans.
There is a clear need for snake repellents for economic and human health and safety reasons, aside from the aesthetic reason for eliminating a pest species from human habitations. As an example, consider the case for the brown treesnake. Brown treesnakes found their way to the island of Guam as a stowaway in cargo in the late 1940""s or early 1950""s. Over the years the population has irrupted, achieving densities of 50-100 snakes/ha. Ecologically, this snake population explosion has been devastating to the island""s ecology. Nine of eleven endemic island birds, 2 lizards, and 1 bat have been driven to extinction by this effective and abundant predator. The high population densities of snakes has also affected the island""s economy, principally by causing power outages when this arboreal snake shorts out electrical power substations. As part of a containment program, the US Department of Agriculture traps and removes snakes around cargo ports to reduce the likelihood that snakes will emigrate to other islands. In addition to the efforts to reduce local populations around high risk shipping and air ports, the USDA inspects cargo using dogs, trained to detect snakes. However, even if a dog were to indicate that a snake may or may not be in pallets of wrapped cargo or cargo containers, there remains a laborious procedure of trying to locate the snake.
Repellents for birds and mammals meeting these safety criteria have been found among natural natural products and human food grade products. Modeling snake repellents after known bird and mammal repellents is unlikely to yield success in identifying snake repellents. Each taxon responds to chemicals as irritants differently. However, species of animals within their respective taxon normally exhibit a uniform response to specific chemical irritants.
Repellency is mediated by chemically sensitive neurons called nociceptors concentrated in the nose, eyes, and mouth. Repellency is the behavioral avoidance of chemicals that promote the sensation of irritation and pain. The important feature for generating the behavioral avoidance to chemical exposure, or repellency, is to expose the nociceptors to the irritating chemicals. Vapor and aerosol repellents that could be applied via portable devices and that would motivate the snake to leave a potentially inaccessible refugium are needed. Natural products and human food grade products with well described human safety information that might also serve as snake repellents would significantly reduce registration costs because significant waivers for toxicity could be obtained.
Snake repellents having a repellent composition, an inert carrier and an adjuvant, and methods to use the snake repellents are disclosed. The repellent composition includes at least one essential oil chosen from the group of anise oil, banana oil, cinnamon oil, clove oil, eucalyptus oil, ginger oil, peppermint oil, oil of wintergreen, sage oil, cedarwood oil, citronella oil, juniper berry oil, and rosemary oil, or at least one reagent derived from these oils chosen from the group of iso-amyl acetate, menthone, methyl anthranilate, eugenol, alpha-pinene, ethyl phenyl acetate, nerol, ethyl butyrate, limonene, linalool, alpha-terpinene, cineol, methyl salicylate, anethole, m-anisaldehyde, citral, geranial acetate, and cinnamaldehyde. Methods to deliver the snake repellents to snakes via aerosol, pressurized vapor, or heated vapor for the purpose of increasing penetration of the snake repellent into the targeted application space and methods to deliver aerosol snake repellents for the purpose of deterring aggressive and attack behavior by snakes so as to enhance human health and safety are disclosed.